This 6-piece piston and ring set is designed for rebuilding N52B25 2.5L engines.It is compatible with E60, E90, E92, 323i, 525i, X1, X3, and X4 models.The set includes six pistons and matching rings with an 82.00mm bore diameter and an 11:1 compression ratio, suitable for naturally aspirated applications.Pistons feature a 20mm wrist pin diameter and 46mm wrist pin length.Ring dimensions are 1.2mm (first ring), 1.5mm (second ring), and 2.0mm (oil control ring) to proper sealing and combustion efficiency.Components are manufactured to meet precise tolerances for engine.